Pages where the terms "Historic Textbook" and "Historic Embryology" appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms and interpretations may not reflect our current scientific understanding. (More? Embryology History | Historic Embryology Papers)

Pages where the terms "Historic Textbook" and "Historic Embryology" appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms and interpretations may not reflect our current scientific understanding. (More? Embryology History | Historic Embryology Papers)

The Hormones in Human Reproduction

To the young physicians and biologists, Fellows of various foundations and scientific societies, who came from other lands to study with the author of this book problems common to all humanity Sidney Arthur Asdell, Cambridge, England Seitchi Saiki, Tokyo, Japan Eduardo Burster Montero, Santiago, Chile Friedrich Hoffmann, Dusseldorf, Germany Graham Weddell, London, England Ines Lopez Colombo de Allende, Cordoba, Argentina Luis Vargas Fernandez, Santiago, Chile Washington Buno, Montevideo, Uruguay

WE TOOK counsel TOGETHER AND WALKED IN THE WAY OF TRUTH AS FRIENDS

Copyright 1942, 1947 by Princeton University Press

GEORGE W. CORNER was born in Baltimore and
studied at The Johns Hopkins University and its medical
school. He holds honorary degrees from the Catholic University of Chile, the University of Rochester, Boston University, Tulane, Temple, Oxford and the University of
Chicago. Now professor emeritus of embryology at Johns
Hopkins, Dr. Corner has also taught at the University of
California, Rochester and Oxford, and has held chairs
both at the Carnegie Institute and at the Rockefeller Institute. He is an honorary member and fellow of many
American and foreign societies in the fields of anatomy
and embryology and is the author of numerous books in
those fields, as well as in medical history. He lives in
Philadelphia where he is the Executive Officer of the
Amepican Philosophical Society.

Preface

THIS book represents, with considerable additions, the substance of the Vanuxem Lectures, given at Princeton University in February 1942. The invitation to be Vanuxem Lecturer carried with it the expressed wish of the Committee that I should discuss the hormones of the reproductive system for the benefit of a general audience, assuming on the part of my hearers no familiarity with biology. This imposed no easy task, for it called upon me to describe some of the most intricate and elaborate mechanisms of the body, to listeners who perhaps had never seen the organs and tissues in which these activities take place. The structure of the living cells and the manner in which they are put together to form the organs are matters not merely so unfamiliar, but actually even so daunting to most people, as to create serious difficulties for the biologist and physician who tries to explain his work. For the first time in my life I could have wished I were an astronomer or physicist, for the heavenly spheres, their orbits and attractions, and even such matters as warps in space and corpuscles of light can be described to a certain extent in terms of the workshop and the household; but how can we explain the marvels of the human egg or the action of an estrogenic hormone without a background of cellular biology.'* My only recourse has been to begin at the very beginning, to devote as many as three chapters to general preparation for actual discussion of the hormones, and at every step to explain and illustrate the underlying anatomy and physiology as clearly as possible. This is, to the best of my knowledge, the first time an American university has devoted one of the great endowed lectureships to the subject of human reproduction. A few years ago it might even have been impossible to break through the old conventions that hampered free public discussion of this subject. We have a tradition that sex and reproduction must be attended by privacy, dignity and romance. It is a good tradition, provided we add a fourth attribute, namely understanding; for otherwise the fundamental life activities concerned in sex may become involved in fears, inhibitions and blind taboos. I emphasize the importance â€” nay even the necessity â€” of instruction and understanding in matters of sex, in case there are still among my readers some who are troubled by our free discussion of intimate functions, and especially in case it seems to them that the dignity and the romance of life are threatened by frank acceptance of the animal nature of mankind or by our use of other creatures to explain human affairs. There is of course no denying that man is an animal, and since human physiology cannot always be subjected to direct experiment (particularly in this field of investigation), we must study the lower animals not only for their own intrinsic interest but also in order to understand ourselves. It is equally true that man is more than an animal. The ape, the tiger, and the worm mate and reproduce their kind, and so do human beings, but only man tries to understand what he is doing and why he does it. In such understanding and in right living based upon knowledge lies our best hope of attaining dignity, honor and beauty in the physical life of mankind.

A book of this kind rests upon the laborious work of many scientific^ investigators. The author, in drawing freely upon the writings of his colleagues, has endeavored to acknowledge their contributions as fully as possible, by mention in the text, footnotes and legends. References however are necessarily limited; readers who wish to consult the original literature will find full bibliographies in Appendix II, note

1. Many fellow workers who have generously permitted the use of illustrations, as indicated in text and legends, deserve especial thanks.

The quotation at the head of Chapter I is from Two Lives, by William EUery Leonard, copyright 1922, 1925, by permission of the Viking Press, Inc., New York. The quotation from C. Day Lewis's translation of Virgil's Georgics, in a footnote to Chapter III, is used by permission of Jonathan Cape, Limited, London and Toronto.

The author's wife, Betsy Copping Corner, and his son, Dr. George W. Corner, Jr., have given unfailing encouragement and have been patient and thoughtful critics. Mr. Arthur G. Rever has been good enough to read the manuscript and has made useful suggestions.

The author's researches upon the menstrual cycle of monkeys, cited in this book, were aided by grants to the University of Rochester by the Rockefeller Foundation and the John and Mary R. Markle Foundation.

Contents

Simple division into parts a frequent mode of reproduction in lower animals; necessity of egg and sperm cells in higher and more complicated creatures ; the participation of two individuals, male and female, essential to the process in all higher animals ; in mammals, including mankind, the fertilized egg sheltered and nourished within the mother's body; correlation of the various organs of the reproductive system to this end by action of chemical substances (hormones) made in the sex glands.

The egg a cell growing in a cavity (follicle) in the ovary; its progress, after discharge from the ovary, via the oviduct to the uterus ; its implantation in the uterus, if fertilized by a sperm cell ; division into many cells and development into an embryo ; nourishment from the mother's blood during growth in the uterus, through an organ of attachment, the placenta.

Development of the eggs of mammals to maturity at regular intervals; occurrence, in most mammals, of a phase of sexual responsiveness (estrus) at the time of ripening of the eggs ; resultant mating, and fertilization of the eggs ; the reproductive cycle constituted by recurrence of these events; peculiar modification of the cycle in the human race, apes and higher monkeys, characterized by monthly disturbance in the uterus resulting in menstruation.

Production by the ovaries of a remarkable substance, the estrogenic hormone ; its property of causing the other organs of the reproductive tract (oviducts, uterus, vagina, mammary glands) to grow to adult size, and of maintaining them in the adult state.

Conversion of the ovarian follicle, after discharge of the egg, into a temporary gland of internal secretion, the corpus luteum; production by this gland of a hormone called progesterone, which acts upon the uterus in such a way as to insure attachment and nourishment of the early embryo.

Menstruation a peculiar phenomenon limited to a few species of higher animals ; its period (in humans) about four weeks, but not perfectly regular. Digression about the cycle in general, showing that it is probably due to interaction between the ovaries and the pituitary gland. Menstruation a periodic breakdown of the uterine lining (endometrium) when the corpus luteum retrogresses. Occurrence, however, of anovulatory cycles, without a corpus luteum, and without "premenstrual" changes. Explanation of the bleeding as due to shutting oflf of the coiled arteries of the endometrium caused by deprivation of estrogenic hormone or of progesterone; bleeding due to progesterone deprivation believed to be a special case of estrin-deprivation bleeding. Theory of the menstrual cycle based on these ideas. The significance of menstruation unknown.

Calculation of the quantities of the two hormones produced in the ovaries and the rate at which they are secreted; in the case of the corpus luteum, discussion of such questions as the amount of hormone made by a single cell, the amount made by the whole gland in one day, and divers other matters of interest concerning the quantitative aspect of ovarian function.

The maintenance of pregnancy a complex aÂ£fair, dependent partly on the hormones. The placenta as a source of gonadotrophic and estrogenic hormones ; progesterone also apparently made by the human placenta. Lactation induced by a special hormone of the pituitary gland.

The testis constructed of tubules in which the sperm cells are made; the interstitial cells. The seminal ducts, seminal vesicles, and prostate gland under control of the testis through its hormone. Secondary sex characters described and shown to be controlled by the testis. Chemistry and effects of the androgenic hormones.

APPENDIX.

CHEMICAL STRUCTURE OF THE SEX GLAND HORMONES

LIST OF PLATES

Plate Facing Page

I. REPRODUCTION BY BUDDING, IN HYDRA 8

n. SEXUAL REPRODUCTION IN HYDRA 9

III. FERTILIZATION AND DIVISION OF THE EGG OF THE

SEA URCHIN, AS SEEN IN SECTIONS 18

IV. DEVELOPMENT OF THE SEA URCHIn's EGG, FROM LIVING SPECIMENS 19

V. THE HUMAN OVARIES, OVIDUCTS, AND UTERUS S4 VI. REGNER DE GRAAf's ORIGINAL PICTURE OF THE

GRAAFIAN FOLLICLE, 1672 S5 VII. THE PRIMATE OVARY AND EGG 38 VIII. GROWTH OF THE FOLLICLE IN THE RAT 89 IX. THE CORPUS LUTEUM 44 X. THE OVIDUCT ( FALLOPIAN TUBe) AND THE TRANSPORT OF THE EGG 45 XI. DIVISION OF THE RABBIt's EGG, FROM LIVING SPECIMENS 56 XII. IMPLANTATION OF THE EMBRYO IN THE RHESUS

MONKEY AND IN MAN 57

XIII. THE VAGINAL CYCLE IN THE RAT 74

XIV. CASTRATE ATROPHY 76 XV. THE EFFECT OF ESTROGENIC HORMONE ON THE

VAGINA 84

XVI. THE EFFECT OF ESTROGENIC HORMONE ON THE

UTERUS 85

XVII. PROGESTATIONAL PROLIFERATION OF THE UTERUS 108

XVIII. THE EFFECT OF PROGESTERONE ON THE UTERUS

AND EMBRYOS OF THE RABBIT 109

XIX. X-RAY PHOTOGRAPH OF THE HUMAN SKULL, SHOWING LOCATION OF THE PITUITARY GLAND 142 XX. HUMAN INFANT AT BIRTH, WITH PLACENTA 143 XXI. THE UTERUS OF THE RHESUS MONKEY AT SUCCESSIVE STAGES OF THE CYCLE 148